Hi Dorothy,

I was looking for this question earlier. The incidence appears low on surveillance testing. There was one paper reporting an RSV-Influenza co-infection rate of 4.65% (see Mexico study below), however the sample size is low. However, there are couple of publications which demonstrate detected co-infection. Here are the ones that I found:

1) Human respiratory syncytial virus in children with lower respiratory tract infections or influenza-like illness and its co-infection characteristics with viruses and atypical bacteria in Hangzhou, China (J Clin Virol. 2015 Aug;69:1-6. doi: 10.1016/j.jcv.2015.05.015. Epub 2015 May 21.)

2) Respiratory viral coinfections identified by a 10-plex real-time reverse-transcription polymerase chain reaction assay in patients hospitalized with severe acute respiratory illness--South Africa, 2009-2010. (Emerg Infect Dis. 2015 Apr;21(4):600-8. doi: 10.3201/eid2104.141033.)

3) Viral coinfection in acute respiratory infection in Mexican children treated by the emergency service: A cross-sectional study. (Ital J Pediatr. 2015 Apr 18;41:33. doi: 10.1186/s13052-015-0133-7.)

Hope this helps and good luck.

Hi Dorothy,

Not sure whether your question is in relation to a particular setting or age group, and whether you’re interested in the absolute number of co-infections or represented as the proportion of individuals tested?

We’ve recently published a comprehensive epidemiological study on viral respiratory infections based on 44,230 episodes of respiratory illness, representing patients attending primary and secondary healthcare services in a major UK population between 2005 and 2013. Each patient was virologically tested as part of routine diagnostics for eleven groups of respiratory virus using contemporary multiplex real-time RT-PCR, thereby providing information on multiple infections that is unbiased by testing decisions (although bear in mind that there is still the potential for an age-dependent bias in swabbing decisions that could have altered over time).

Among 27,284 patient episodes of respiratory illness that were tested for all eleven groups of respiratory virus (there were some periods of partial testing that we excluded from analyses), we found that most viruses were co-detected with each other virus at least once. However, we found that the pattern of mixing among the virus groups was non-random. Amalgamating all patient groups across the nine years of testing, I can let you know that we observed n=26 RSV/influenza A co-infections (representing 6% of the 420 co-infections involving RSV, and 2% of the total 1266 RSV detections among the 27,284 patients) and n=8 RSV/influenza B co-infections (representing 2% of the 420 co-infections involving RSV, and 0.6% of the total 1266 RSV detections among the 27,284 patients).

Hope this helps. The specific figures detailed above are not published, however, I've attached a link to the paper for further information:

Article Extensive multiplex PCR diagnostics reveal new insights into...

Thanks... this was an "FYI" for my fellow co-workers who told me that it was impossible to concurrent infects to exist... even though I nknew better.  I wanted to show studies that say nto the contrary. Again Thanks ~ Dory